Delete duplicate rows with same id in mysql. Ensure your database remains clean and organized.

Delete duplicate rows with same id in mysql. Here we go! Before We Start Jul 5, 2022 · Query a table and get all the ID's of all the duplicate rows (or ideally all the IDs except the ID of the first instance of the duplicate). First, create your temporary table inserting not duplicated record: CREATE TABLE newtable SELECT * FROM oldtable GROUP BY name; Then delete old table with duplicated records TRUNCATE TABLE oldtable; Then import data from temporary table to Nov 19, 2024 · Learn to find and delete duplicate rows in MySQL using GROUP BY and HAVING clauses. Jun 28, 2016 · The closest I can find to what I want to do is How to duplicate related rows, but my inexperience gets me lost. (You can then drop that index if you need future duplicates and/or know they won't happen again). Aug 29, 2020 · I have searched numerous answers in here stackoverflow but I can't seem to understand how to delete duplicate rows. Jan 26, 2024 · In this guide, we’ll explore a variety of strategies to remove duplicates from a MySQL table, providing you with the knowledge to choose the best approach for your specific scenario. Jul 25, 2019 · If you can have duplicate rows with the same data in all columns, then there is no way to delete a row without deleting its duplicates. Jul 30, 2016 · I want to delete all rows with the same values in all columns except id, except the row with the lowest id. Use ROW_NUMBER, CTE and DELETE techniques to clean up your database and improve performance. Aug 19, 2024 · Why Count Duplicates in MySQL? Counting duplicates is essential for several reasons: Data Integrity: Duplicate records can lead to inaccurate reporting and skewed results, making it important to identify and address them. Data Cleansing: Removing duplicates helps maintain a clean and reliable database, improving performance and accuracy. 9月28日，《花花公子 Playboy》杂志的创始人休·赫夫纳Hugh Hefner安然离世。 杂志官网为他的照片上配了这句名言： “生命太短暂，不该活在别人的梦里。 花花公子的创始人，Hugh Hefner逝世，享年91岁。 这个游戏花丛，创造了著名的兔女郎形象，曾经约会过千余女性的浪子，最终将长眠在缔造他一生传奇的… 主编 休·海夫纳 （Hugh Hefner）是个思想开放的芝加哥小伙，他在学校当了学生会主席和校刊编辑。人缘不错，文笔也不错的海夫纳在毕业后决定一鸣惊人，决定创建一本名为“ 雄鹿舞会 ”（Stag Party）的色情杂志（雄鹿有单身男子的意思），并用鹿头作为标志，但名为“雄鹿”的杂志已经存在，计划 《花花公子》的创始人休·海夫纳（Hugh Hefner）曾经描绘了这样一幅场景，“我们应该享受这样的生活：在自家的公寓中，调上一杯鸡尾酒，准备两份开胃小吃，唱机里放上一段背景音乐、邀请一位红粉佳人，静静地讨论尼采、爵士乐和性。 Aug 24, 2025 · 至于兔女郎，那更是与著名的《playboy》有关。 对于精明的《playboy》创始人休·海夫纳（Hugh Hefner）而言，只要解决了“如何让【欲念】具象为可以接受的寻常物”的问题，就能直击那个时代男人的痒点与女人的痛点（ps 女权运动的开展）。 乐队录音时住的酒店是著名 《花花公子》 杂志创造者 Hugh Hefner 于1968年就在这里开了第一个花花公子度假村。 虽然它在1982年就关闭了，但在其原址上开起来的 Alpine Valley Resort 是个十足的摇滚圣地。 从军队退伍之后他回到了芝加哥，并开始给杂志投稿，直到1956年，他遇到了休·赫夫纳（Hugh Hefner），《花花公子》的创始人。 他开始为《花花公子》创作插画，同时也把他的旅游经历写成文章发表。 大家也都知道我朝的目标好似Hugh Hefner的girlfriend一直在变乐此不疲，一开始是「解放全世界」。 后来改小了点成了「赶英超美」，发现不现实后又变成了「四个现代化」。 一看也是无望，算了算了，低调地成了社会主义初级阶段，目标「实现小康」！ 《花花公子》的创始人Hugh Hefner也对他们表示了大力支持。 通过他们的方法，能够短期快速的解决问题，治疗成功率 高达80%。 但是尽管如此，在《海斯法典》严格执行的年代，大多数违反规定的影片终究还是遭到了严苛的限制，成人动画境遇也同样如此。 直到1953年，《花花公子》（Playboy）杂志由休·赫夫纳（Hugh Hefner）在芝加哥创刊，从此这本涉足情色的刊物很快便在美国大放异彩。. In my case, delete rows with the same pd in a td. One possible solution is to add (not re create/ re publish) a column with unique values to your table, then delete the duplicate rows you want How can I check if a table contains duplicate rows, with the same value of the couple (date, time) ? How can I remove all but one row ? Id is a sequential number that I increment after every post, How can I delete duplicate rows where no unique row id exists? My table is col1 col2 col3 col4 col5 col6 col7 john 1 1 1 1 1 1 john 1 1 1 1 1 1 sally 2 2 2 Mar 30, 2022 · You may have faced several situations where the same rows in a MySQL table are inserted twice or more. Foreign keys and triggers will remove related rows in other tables, and the rows will be re-inserted. The following statement deletes duplicate rows and keeps the highest id: Jul 13, 2018 · I am doing some data clean up and I would like to remove duplicate rows by finding records that have the same "picture id" and "date" values: Example: picture_id - 2 date - "13-Jul-18" picture_id The MySQL Delete Duplicate Records Duplicate records in a database, including MySQL, is a very common occurrence. So use the following query to check which rows are duplicates, and also see the count of duplicate rows. Basically, I want to copy a number of records, change one column and insert them back Jan 1, 2016 · Having two or more rows with identical values is a sign of very bad design. Feb 2, 2024 · You can use the following syntax in MySQL to delete all duplicate rows in a table but keep the one with the latest id value: DELETE t1 FROM athletes t1, athletes t2 Jul 23, 2025 · Using the DELETE Statement Using the DISTINCT Keyword Using the GROUP BY Clause Using the HAVING Clause Demo MySQL Database Let's look at different ways to delete duplicate rows from a table in MySQL with these practical examples. Emails get duplicated. How do I remove duplicate rows from a table in SQL? Oct 29, 2024 · Explore the different methods for filtering out and permanently removing duplicate rows using SQL. Remove Duplicates Using Row_Number () what in case when id 100 is already there. Knowing how to remove duplicates while retaining a single, unique instance of each entry can optimize storage and improve query performance. e. I wonder how did you end up in this situation. Mar 16, 2022 · Hello everyone, I have a problem, I have several records with the same ID and I would like to eliminate the duplicate records but leaving only one. What I've tried as the select query: DELETE FROM `users_acl` WHERE userID I Apr 11, 2015 · I have a table that has a the following columns: ID(primary key), USER, ACTION TIME LOCATION I am trying to remove duplicate entries using the columns: USER, ACTION, TIME, LOCATION together. This query does that for all rows of tablename having the same column1, column2, and column3. In this tutorial, you will learn how to delete duplicate rows in MySQL by using the DELETE JOIN statement or an immediate table. Apr 1, 2022 · Find Duplicate Rows Let’s check if there exist any duplicate rows. Secondlty if you choose any new id for your new row, and during the operation someone else insert a new row and then your id and the newly inserted id will be the same. The existing row should be automatically modified. However, that still left rows whose IDs and names were the same, in other words, where entire rows were duplicated. Dec 13, 2021 · Most of the examples shows deleting duplicate entries with ID or primary key. tv, welches ein Webportal für das Livestreaming von Videospielen ist. With ON DUPLICATE KEY UPDATE, the affected-rows value per row is 1 if the row is inserted as a new row, 2 if an existing row is updated, and 0 if an existing row is set to its current values. Dec 6, 2023 · Our query has resulted in duplicate rows; the first two rows have the same values in both columns (Bark, aged 10). Right now I have the following mysql statement: May 6, 2014 · FROM TableName GROUP BY data,value) Explanation: With the given example, inner query will return ids (1,6,4,5,7). Mar 24, 2017 · Select rows with same id but different value in another column Asked 11 years, 8 months ago Modified 6 years, 9 months ago Viewed 510k times This tutorial shows you step by step how to find duplicate values in one or more columns in MySQL by using pure SQL statement. In this case, we're choosing how exactly we want to delete the duplicates. tv (stilisiert twitch), ist ein US-amerikanisches Live-Streaming - Videoportal, das vorrangig zur Übertragung von Videospielen und zum Interagieren mit Zuschauern im Chat genutzt wird. How can I achieve this? Jul 9, 2024 · In MySQL, remove duplicate records while preserving one representative entry using a DELETE statement with a self-join. I'd like to only keep one row for each. Jul 23, 2025 · To find duplicates in these three columns, group the rows by OFFICER_NAME, TEAM_SIZE, and POSTING_LOCATION, we can group the data by these columns and filter the results with HAVING clause, using the COUNT() function. Today’s Jul 11, 2025 · Therefore, removing duplicate records ensures better data integrity and more efficient database operations Fortunately, there are more efficient methods to remove duplicates from SQL queries without using DISTINCT. This guide provides solutions for handling duplicates and ensures that only unique rows remain in the database. Aug 27, 2018 · The best option is to extract desired records to a temporary table, then delete the main table and then import records from temporary to the main table. Ensure your database remains clean and organized. CTEs and ROW_NUMBER () will not help you in this case, because you can't delete from a CTE in MySQL. To be more precise, in most cases, duplicate records do not have the exact same values in every column, as at least the value of the primary key column is different. Feb 8, 2024 · So ist Twitch ist die Abkürzung von Twitch. Oct 22, 2024 · The 3 simple methods to delete duplicate rows in MySQL are using the DELETE JOIN statement, using the ROW_NUMBER () function, creating a new temporary table to store distinct records, and then May 16, 2011 · H ow do I remove duplicate data or rows from a MySQL query? If output from a MySQL query contains duplicate data or row and if you would like to remove the same use DISTINCT. Select the Duplicate Rows to Keep or Delete After identifying duplicates, we need a method to remove them. The How to Spot and Delete Values with Duplicate Meaning in MySQL blog dealt with Duplicate Meaning; the follow-up addressed how to identify Non-unique Keys. May 27, 2024 · Learn how to remove duplicates in SQL with our detailed guide. Sie können sich dort kostenlos anmelden, beliebige Spiele spielen und Twitch is an interactive livestreaming platform for gaming, entertainment, sports, music, and more, connecting millions of users worldwide. I Nov 11, 2024 · Explore various solutions to find and manage duplicate records in MySQL with examples and step-by-step instructions. One way to do it will be using the foll Feb 2, 2024 · This tutorial explains how to delete duplicate rows from a table in MySQL but keep the latest, including an example. The first two rows are duplicates (except for the DogId column, which is the table’s primary key, and contains a unique value across all rows). May 15, 2023 · Auf Twitch können Sie Ihren Lieblingsstreamern komplett kostenfrei und ohne eigenen Account zuschauen. The last three rows are also duplicates (except for the DogId column). I have a table that has a lot of duplicates in the Name column. That’s where two records in the same table have the same key, but may or may not have different values and meanings. Jan 8, 2025 · In MySQL, a duplicate record is a row in a table that shares identical values across all or a significant subset of columns with other rows. This is the case if existing duplicates might hold old information – in all columns, or just in some columns. Sep 4, 2015 · Here's an example of how the table looks (example with one id_product_attribute number): So I want to delete the duplicate currencies for EACH id_product_attribute. I Jul 28, 2019 · Self join is a good option but to have a faster function it is better to first find rows that have duplicates and then join with original table for finding id of duplicated rows. Lade Twitch herunter und amüsiere dich mit Live-Games, Musik, Sport, e-Sport, Podcasts, Kochshows, IRL-Streams und was sonst noch so durch die wunderbar verrückten Köpfe unserer millionenstarken Community schwirrt. Mar 28, 2024 · There are multiple approaches to detecting and removing duplicate rows in MySQL tables, and we have reviewed them in this article. To define a key on the table, we have to delete the duplicate rows from the table. Jan 30, 2018 · Removing Duplicate Rows from the amalgamated_actors Table In the How to Delete Duplicate Rows with Different IDs in MySQL (Part 3) blog, we successfully removed rows that contained duplicate names. SQL DELETE DUPLICATE ROWS When dealing with large datasets, it's common to encounter duplicate records in a table. Jan 23, 2023 · In this post, we'll show you how to efficiently remove duplicate rows in MySQL using both SQL queries and a programming language like PHP. A table may contain duplicate rows if the key not defined. The article presented four options for deleting duplicates in MySQL and provided examples. Download Twitch and join millions enjoying live games, music, sports, esports, podcasts, cooking shows, IRL streams, and whatever else crosses our community’s wonderfully absurd minds. Find all rows that are duplicates and delete all but the one with the smallest id. id = us. Learn the practical applications of how to remove duplicates in SQL Server, MySQL, and PostgreSQL. For MYSQL, an inner join (functional equivalent of EXISTS) needs to be used, like so: The best way to delete duplicate rows by multiple columns is the simplest one: Add an UNIQUE index: ALTER IGNORE TABLE your_table ADD UNIQUE (field1,field2,field3); The IGNORE above makes sure that only the first found row is kept, the rest discarded. Mar 27, 2009 · For removing duplicate rows with multiple fields , first cancate them to the new unique key which is specified for the only distinct rows, then use "group by" command to removing duplicate rows with the same new unique key: Oct 25, 2017 · I have a mysql table, simplified version below: ID Col1 Col2 CreatedDate 232 my data some data 2017-10-15 8:50:20 232 my data some data 2017-10-14 8:52:20 232 my data some data 2017-10-13 8:53:20 232 my data some data 2017-10-12 8:55:20 232 my data some data 2017-10-11 8:54:20 ID is int and CreatedDate is datetime I want to keep the most recent two rows and delete all other with the same id. You can limit the number of delete rows using LIMIT though: DELETE FROM orders WHERE id_users = 1 AND id_product = 2 LIMIT 1 But that just solves your current issue, you should definitely work on the bigger issue by defining primary keys. 1. Jan 16, 2018 · January 16, 2018 by Robert Gravelle The majority of duplicate records fall into one of two categories: Duplicate Meaning and Non-unique Keys. Need to clean up duplicate rows existing in existing tables? Use Group By, Self Join, or Window Function techniques to find and remove duplicate rows. I have a table with columns for ID, firstname, lastname, address, email and so on. We can do this using a self Feb 14, 2022 · How to delete duplicate records when both rows the exact same records? create table item (id int, product_name varchar (20), quantity int, amount decimal (10,2) ); insert into item values (1,"La Jun 23, 2024 · Delete the duplicate row but keep oldest: using ROW_NUMBER () Duplicate records can create a serious issue. Having duplicate rows isn’t necessarily a bad thing. This redundancy might occur due to various reasons − The row might be inserted twice. May 24, 2011 · I have unique id and email fields. With duplicate data it is possible for orders can be created many times, It can give inaccurate results. When raw A frequent question in IRC is how to delete rows that are duplicates over a set of columns, keeping only the one with the lowest ID. The row should be completely replaced. The following query uses the concept of the nested query by selecting all the rows that have duplicate records with the lowest customer id. Sep 24, 2013 · Now I want to delete the duplicate rows from the table I am using this query to select or count number of duplicate records SELECT NameCol, COUNT(*) as TotalCount FROM TestTable The majority of duplicate records fall into one of two categories: Duplicate Meaning and Non-unique Keys. I want to pull out duplicate records in a MySQL Database. Suggestion: Use the first method since it is faster than the latter. January 16, 2018 by Robert Gravelle The majority of duplicate records fall into one of two categories: Duplicate Meaning and Non-unique Keys. The WHERE clause in this case allows MySQL to ignore any row that doesn't have a duplicate and will also ignore if this is the first instance of the duplicate so only subsequent duplicates will be ignored. The choice depends on your unique conditions, work requirements, and preferences. Feb 2, 2024 · Using INNER JOIN with the Delete statement allows you to remove duplicate rows from your table in MySQL. Jul 22, 2025 · Explore various methods to effectively eliminate duplicate records from your MySQL database tables, ensuring data integrity and performance. Sep 4, 2018 · (row_id,user_id, stat1,stat2,, statN, timestamp) Now I want to remove all duplicate records, where user_id and stat columns are the same, but only between other rows with different data. January 16, 2018 by Robert Gravelle The majority of duplicate records fall into on e of two categories: Duplicate Meaning and Non-unique Keys. Not only one but we will see three simple and easy methods to delete duplicate rows from the table. The following lists the duplicates, but I don't know how to delete the duplicates and just k Sep 26, 2024 · This query groups the records based on the columns first_name, last_name, and email, and shows only the groups with more than one occurrence, i. To do this, sort the table using the column on which the key to define. A common approach is to keep the record with the smallest or largest id and delete the others. There’s always something live and new on Twitch. So, there can be 3 , 4 or maybe more identical records but i have to delete all and keep only one. Learn how to clean your database efficiently and improve query performance. However how would I retain one entry whilest removing the other ones? Jan 16, 2018 · January 16, 2018 by Robert Gravelle The majority of duplicate records fall into one of two categories: Duplicate Meaning and Non-unique Keys. So here is the number of ways to perform the task of MySQL delete duplicate rows but keep one. So, in this tutorial, we are going to learn how to delete duplicate data from the table. If multiple rows found with the same data, then follow the below process to delete the duplicates before In general, you should try to avoid using an ON DUPLICATE KEY UPDATE clause on tables with multiple unique indexes. Jan 30, 2018 · A query which will delete the first or maybe the second row but keep one record. Nov 14, 2024 · Removing duplicate rows in MySQL tables is a common need, especially for databases that store repetitive data entries. Feb 19, 2022 · The duplicate rows share exactly the same values across all columns except for their primary key/unique ID column. I don't want to re create or re publish data with distinct values into the table. What is the query to find all duplicates? This is for MySQL and I would like to see duplicate rows Oct 2, 2018 · GROUP BY student_id, class_id HAVING COUNT(*) > 1) t ON t. Aug 22, 2013 · All tables should have a primary key (consisting of a single or multiple columns), duplicate rows doesn't make sense in a relational database. As we expect that for each ‘ bin_id ‘ and ‘ date ‘ combination only one row should exist. Now, a record is said to be duplicated when two or more rows in a database table have same values. Twitch, auch Twitch. Always test your queries on a backup or development environment to ensure accuracy before applying them to production databases. It is very important to ensure that no duplicate data resides in the table. Apr 11, 2025 · Find and delete duplicate rows in MySQL using GROUP BY and HAVING clauses. Jul 23, 2025 · Using methods like GROUP BY, ROW_NUMBER(), and CTE, we can efficiently delete duplicate rows in SQL while retaining unique records. This fiddle shows the records which are going to be deleted using this method. Jun 20, 2024 · After reading this tutorial, you should be able to remove duplicate rows in a MySQL table and improve your database performance. This can be done with: SELECT address, count(id) as cnt FROM list GROUP BY address HAVING cnt > 1 Which results in: 100 MAIN ST 2 I Jun 27, 2025 · In SQL, perfectly identical rows are the ones where, despite identical data values across all relevant columns, each row is technically distinct due to an underlying, often auto-generated, identifier (like an AUTO_INCREMENT or IDENTITY column). I only want to keep one Email address of all the duplicates but with the latest id (the last inserted record). . Is there any way to delete duplicate email addresses from the TABLE? Additional information (from comments): If Twitch Twitch is an interactive livestreaming service for content spanning gaming, entertainment, sports, music, and more. Feb 2, 2024 · This tutorial explains how to delete rows from a table in MySQL based on id values, including several examples. Jul 23, 2025 · To delete duplicates based on one column, use a self-join on the table and delete the rows where the EMPLOYEE_ID is greater than the matching duplicate record. A MySQL database stores data in the form of tables consisting of rows and columns. This is the bottle neck in this code have. However, there is no id for each row. Any ideas with a mysql statement? Aug 15, 2018 · I need to delete the duplicate records in this table. could return any of the IDs from the duplicate rows. 2. Match records based on criteria like identical values in a column and delete duplicates based on conditions, such as retaining the record with the lowest ID, ensuring data cleanliness, and reducing redundancy in the It's not an exact duplicate question, as this asks specifically for a DELETE command to perform the same action that an ALTER command adding a unique index would be needed to have MySQL automatically remove duplicate rows. So as a first step, we have to check the table has a duplicate row or not. The outer query will delete records from table whose id NOT IN (1,6,4,5,7). Also ein bisschen wie YouTube für Gaming - nur eben live. Includes clear syntax, step-by-step instructions, and practical examples for easy understanding. Sep 10, 2025 · Learn how to delete duplicate records in SQL efficiently. Given this data: id year file name language download 1 2014 a x h d 2 2 I have a table with the following fields: id (Unique) url (Unique) title company site_id Now, I need to remove rows having same title, company and site_id. In this tutorial, we’ll explore different methods to delete all the identical rows in SQL. May 8, 2025 · We’ll just ignore duplicates. Aug 31, 2014 · Need some help on a MySQL query to delete the rows where the userID count is greater than one and has an acl value=4. , duplicates. I have a table here with a name May 8, 2011 · 7 Suppose I want to alter the table so that my primary keys are as follows user_id , round , tournament_id Currently there are duplicates that I need to clean up. Lade Twitch herunter und amüsiere dich mit Live-Games, Musik, Sport, e-Sport, Podcasts, Kochshows, IRL-Streams und was sonst noch so durch die wunderbar verrückten Köpfe unserer millionenstarken Watch esports pros, catch a live tour of Tokyo, or learn how to bake. Problem Statement Jul 22, 2025 · Explore effective SQL strategies for deleting duplicate rows, keeping either the oldest or newest record based on ID, and alternative methods for performance. I suppose model_id is the table's primary key. Feb 7, 2022 · MySQL provides you with the DELETE JOIN statement that allows you to remove duplicate rows quickly. id But it deletes the MAX (ID) and it is retaining the the other duplicates and it is the opposite of what I want. we will first create a sample customers table and insert duplicate values in it. Example Data product amount quantity table 2000 5 chair 300 25 TV 30000 4 bike 300 25 table 2000 5 chair Feb 10, 2015 · Note: which row's ID this keeps (from the duplicates) is not specified in MySQL - because SELECT ID,targetField . trl gem fqlakr gfkpbavm rdf jeqw rufs umlszsoz pbwu qamf